To increase colorectal cancer (CRC) screening rates in underserved populations, new decision tools are needed. This project will demonstrate that patient decision-making about cancer screening can be enhanced by modeling and simulating patients' "mental maps" using perceptual mapping methods and vector message design techniques to tailor a CRC decision aid for a population with limited literacy. Our specific aims are to use these methods to 1) understand how patients with limited literacy perceive the two most commonly used CRC screening methods, FOBT and colonoscopy, 2) model and simulate messages based on those perceptions, and 3) use vector message methods to design a literacy-appropriate decision aid from the simulation data. The decision aid designed with these methods will enhance screening decision-making in a population aged 50-70 with 9th grade or lower level of literacy. To do this, we will conduct focus groups with screened and never screened male and female subjects to design instruments to measure CRC risk perception. We will collect risk perception data and use it for perceptual mapping, modeling and computer simulations. These data will yield data for vector message design to develop a decision aid tailored to the mental maps of subjects with limited literacy. To assess the effectiveness of this method for developing a literacy appropriate decision-making tool, we will conduct a pilot study to establish the effect size of the research questions: 1) Experimental subjects counseled with the decision aid designed with perceptual mapping and vector message design techniques will be more likely than controls, counseled with an existing decision aid, to report a) intent to be screened for CRC, b) less decisional conflict, and d) that the decision aid was useful in their decision-making process. Experimental subjects' perceptual maps will also show "self" closer to the decision to be screened than Controls. The impact of developing modeling and simulation methods to improve message design and enhance decision-making is far-reaching. The methods we propose developing have wide application across the cancer continuum from primary prevention and screening to treatment and end-of-life decisions. If successful, these methods can provide a cost-effective way to tailor evidence-based decision aids for patients across diverse literacy levels. Results from this study will be used to develop a fully powered randomized trial that will include actual screening outcomes. [unreadable] [unreadable] [unreadable]